Semiconductor light emitting device

ABSTRACT

Disclosed is a semiconductor light emitting device. The semiconductor light emitting device comprises a first conductive semiconductor layer, an active layer on the first conductive semiconductor layer, and a second conductive semiconductor layer comprising a plurality of recesses on the active layer.

The present application claims priority under 35 U.S.C. 126 to KoreanPatent Application No. 10-2008-0038116 (filed on Apr. 24, 2008), whichis hereby incorporated by reference in its entirety.

BACKGROUND

The present disclosure relates to a semiconductor light emitting device.

Groups III-V nitride semiconductors have been variously applied to anoptical device such as blue and green light emitting diodes (LED), ahigh speed switching device, such as a MOSFET (Metal Semiconductor FieldEffect Transistor) and an HEMT (Hetero junction Field EffectTransistors), and a light source of a lighting device or a displaydevice.

The nitride semiconductor is mainly used for the LED (Light EmittingDiode) or an LD (laser diode), and studies have been continuouslyconducted to improve the manufacturing process or a light efficiency ofthe nitride semiconductor.

SUMMARY

The embodiment provides a semiconductor light emitting device comprisinga compound semiconductor layer provided therein with recesses.

The embodiment provides a semiconductor light emitting device comprisinga plurality of compound semiconductor layers provided at a threadingdislocation region thereof with a recess.

The embodiment provides a semiconductor light emitting device comprisinga compound semiconductor layer and a recess corresponding to a threadingdislocation of an electrode layer.

An embodiment provides a semiconductor light emitting device comprising:a first conductive semiconductor layer, an active layer on the firstconductive semiconductor layer, and a second conductive semiconductorlayer comprising a plurality of recesses on the active layer.

An embodiment provides a semiconductor light emitting device comprising:a substrate comprising a plurality of convex patterns, a light emittingstructure comprising a plurality of compound semiconductor layers on thesubstrate, an electrode layer on the light emitting structure, and arecess formed from the electrode layer to a predetermined position ofthe light emitting structure corresponding to the convex pattern of thesubstrate.

An embodiment provides a semiconductor light emitting device comprising:a light emitting structure having a threading dislocation and comprisinga first conductive semiconductor layer, an active layer on the firstconductive semiconductor layer, and a second conductive semiconductorlayer on the active layer, an electrode layer on the light emittingstructure, and a plurality of recesses formed from the electrode layerto a predetermined depth of the light emitting structure correspondingto the treading dislocation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side sectional view showing a semiconductor light emittingdevice according to a first embodiment;

FIGS. 2 to 12 are views showing a method for manufacturing thesemiconductor light emitting device according to the first embodiment;

FIG. 13 is a side sectional view showing a semiconductor light emittingdevice according to a second embodiment;

FIG. 14 is a side sectional view showing a semiconductor light emittingdevice according to a third embodiment;

FIG. 15 is a side sectional view showing a semiconductor light emittingdevice according to a fourth embodiment; and

FIG. 16 is a side sectional view showing a semiconductor light emittingdevice according to a fifth embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, a semiconductor light emitting device according to theembodiment will be described with reference to accompanying drawings. Inthe description about the embodiment, the size of components shown inthe accompanying drawings is for an illustrative purpose only, but theembodiment is not limited thereto.

FIG. 1 is a side sectional view showing a semiconductor light emittingdevice according to a first embodiment.

Referring to FIG. 1, the semiconductor light emitting device 100comprises a substrate 110, an undoped semiconductor layer 120, a firstconductive semiconductor layer 130, an active layer 140, a secondconductive semiconductor layer 150, a plurality of recesses 160, a thirdconductive semiconductor layer 170, an electrode layer 180, a firstelectrode 191, and a second electrode 193.

The semiconductor light emitting device 100 comprises a light emittingdiode (LED) based on group III-V compound semiconductors, and the LEDmay comprise a color LED emitting blue light, green light or red lightor an UV LED. The light emitted from the LED may be variously realizedwithin the technical scope of the embodiment.

The substrate 110 may comprise one selected from the group consisting ofaluminum oxide (Al₂0₃), gallium nitride (GaN), silicon carbide (SiC),zinc oxide (ZnO), silicon (Si), gallium phosphide (GaP), and galliumarsenide (GaAs). A convex pattern 111 is formed on an upper surface ofthe substrate 110. The convex pattern 111 may have a lens shape or ahemispherical shape to improve external quantum efficiency. The materialand the pattern shape of the substrate 110 may be variously changedwithin the technical scope of the embodiment, but the embodiment is notlimited thereto.

A buffer layer (not shown) is formed on the substrate 110, and thebuffer layer reduces a lattice constant between the substrate 110 and aGaN semiconductor. The buffer layer may comprise a group III-V compoundsemiconductor such as gallium nitride (GaN), aluminum nitride (AlN),aluminum gallium nitride (AlGaN), indium gallium nitride (InGaN), indiumnitride (InN), indium aluminum gallium nitride (InAlGaN), or aluminumindium nitride (AlInN).

The undoped semiconductor layer 120 may be formed on the substrate 110or the buffer layer. The undoped semiconductor layer 120 may comprise aGaN-based semiconductor. At least one of the buffer layer and theundoped semiconductor layer 120 may be formed on the substrate 110, orno layer may be formed on the semiconductor substrate 110.

At least one first conductive semiconductor layer 130 is formed on theundoped semiconductor layer 120. The first conductive semiconductorlayer 130 comprises a group III-V compound semiconductor doped with thefirst conductive dopant. For example, the first conductive semiconductorlayer 130 may one selected from the group consisting of gallium nitride(GaN), aluminum nitride (AlN), aluminum gallium nitride (AlGaN), indiumgallium nitride (InGaN), indium nitride (InN), indium aluminum galliumnitride (InAlGaN), and aluminum indium nitride (AlInN) that aresemiconductor materials having a composition formula ofIn_(x)Al_(y)Ga_(1−x−y)N (0≦x≦1, 0≦y<1, 0≦x+y≦1). When the firstconductive semiconductor layer 130 is an N-type semiconductor layer, thefirst conductive dopant comprises an N-type dopant such as silicon (Si),germanium (Ge), tin (Sn), selenium (Se), or tellurium (Te). The firstconductive semiconductor layer 130 may serve as an electrode contactlayer, and the embodiment is not limited thereto.

The active layer 140 is formed on the first conductive semiconductorlayer 130, and the active layer 140 may have a single quantum wellstructure or a multi-quantum well structure.

In the active layer 140, a quantum well layer and a quantum barrierlayer may be periodically formed by using materials of group III-Vcompound semiconductors. For example, an InGaN quantum well layer/a GaNquantum barrier layer or an AlGaN quantum well layer/a GaN quantumbarrier layer may be periodically formed. The active layer 140 mayselectively comprise materials having band cap energy according to thewavelength of light. The active layer 140 may comprise a materialemitting color light such as blue light, red light, or green light.

A conductive clad layer may be formed on and/or under the active layer140, and may comprise an AlGaN-based semiconductor.

At least one second conductive semiconductor layer 150 is formed on theactive layer 140. The second conductive semiconductor layer 150 maycomprise group III-V compound semiconductors doped with a secondconductive dopant. For example, the second conductive semiconductorlayer 150 may comprise one selected from the group consisting of galliumnitride (GaN), aluminum nitride (AlN), aluminum gallium nitride (AlGaN),indium gallium nitride (InGaN), indium nitride (InN), indium aluminumgallium nitride (InAlGaN), and aluminum indium nitride (AlInN) that aresemiconductor materials having a composition formula ofIn_(x)Al_(y)Ga_(1−x−y)N (0≦x≦1, 0≦y≦1, 0≦x+y≦1). When the secondconductive semiconductor layer 150 is a P-type semiconductor layer, thesecond type dopant comprises a P-type dopant such as Mg or Ze.

The third conductive semiconductor layer 170 is formed on the secondconductive semiconductor layer 150. The third conductive semiconductorlayer 170 may comprise group III-V compound semiconductors doped withthe first conductive dopant. For example, the third conductivesemiconductor layer 170 may comprise one selected from the groupconsisting of gallium nitride (GaN), aluminum nitride (AlN), aluminumgallium nitride (AlGaN), indium gallium nitride (InGaN), indium nitride(InN), indium aluminum gallium nitride (InAlGaN), or aluminum indiumnitride (AlInN) that are semiconductor materials having a compositionformula of InxAlyGa1−x−yN (0≦x≦1, 0≦y≦1, 0≦x+y≦1). When the thirdconductive semiconductor layer 170 is an N-type semiconductor layer, thefirst type dopant comprises an N-type dopant such as silicon (Si),germanium (Ge), tin (Sn), selenium (Se), or tellurium (Te). The firstconductive semiconductor layer 170 can serve as an electrode contactlayer, but the embodiment is not limited thereto.

The first conductive semiconductor layer 130, the active layer 140, thesecond conductive semiconductor layer 150, and the third conductivesemiconductor layer 170 may be defined as a light emitting structure.The first conductive semiconductor layer 130, the second conductivesemiconductor layer 150, and the third conductive semiconductor layer170 may be formed as a P-type semiconductor, an N-type semiconductor,and a P-type semiconductor, respectively. The light emitting structuremay comprise at least one of an N—P—N junction structure, a P—N—Pjunction structure, an N—P junction structure, and a P—N junctionstructure.

The electrode layer 180 is formed on the light emitting structure. Theelectrode layer 180 may be formed on the third conductive semiconductorlayer 170 using a transmissive electrode material. The electrode layer180 comprises at least one of indium tin oxide (ITO), indium zinc oxide(IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO),indium gallium zinc oxide (IGZO), indium gallium tin oxide (IGTO),aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide(GZO), IrOx, RuOx, RuOx/ITO, Ni/IrOx/Au and Ni/IrOx/Au/ITO, but theembodiment is not limited thereto.

The first electrode 191 may be formed in a predetermined region of thefirst conductive semiconductor layer 130, and the second electrode 193may be formed on the electrode layer 180. The second electrode 193 maydirectly/indirectly make contact with the electrode layer 180 and/or thethird conductive semiconductor layer 170, but the embodiment is notlimited thereto.

The semiconductor light emitting device 100 may have a crystal defectoccurring to the surface of the electrode layer 180. The crystal defecthas the form of dislocations (i.e., threading dislocations P1 and P2)vertically propagating from the convex pattern 111 of the substrate 110.The threading dislocations P1 and P2 are generated from the convexpattern 111 of the substrate 110 and pass through the plural compoundsemiconductor layers 120, 130, 140, 150, and 170. Such threadingdislocations P1 and P2 may be used as a current path of a leakagecurrent. If a high voltage such as electrostatic discharge (ESD) isapplied to the semiconductor light emitting device 100, the high voltagemay flow along the threading dislocations P1 and P2. In this case, theactive layer 140 may be broken, and optical power can be reduced.

The recesses 160 are formed in the region of the threading dislocationP1 away from an upper layer of the semiconductor light emitting device100 by a predetermined depth D1. Accordingly, the threading dislocationP1 is not exposed to the surface of the semiconductor light emittingdevice 100. In this case, the recess 160 may not be formed under thesecond electrode 193, thereby preventing the threading dislocation P2from directly making contact with the electrode layer 180.

The depth D1 of the recess 160 may be made from the electrode layer 180to an upper portion of the second conductive semiconductor layer 150through the third conductive semiconductor layer 170. Each recess 160corresponds to the threading dislocation P1. In this case, the recess160 is formed to the electrode layer 180 or to the third conductivesemiconductor layer 170 to remove the threading dislocation P1.

The recess 160 may be formed to the depth D1 corresponding to the convexpattern 111 of the substrate 110.

The electrode layer 180 may not be formed. In this case, the recess 160may be formed to a predetermined depth from the third conductivesemiconductor layer 170.

The recess 160 may have at least one of a polyhedral shape, a reverseconical shape, a polygonal column shape, a cylindrical shape, and ahemispherical shape. The recess 160 may have the maximum width or themaximum diameter of about 10 nm to about 3000 nm and the depth D1 ofabout 10 nm to about 1000 nm. The width of the recess 160 may be changedaccording to the size of the convex pattern 111 of the substrate 110.The recess 160 may have a size based on the light intensity and thelight emitting area of the semiconductor light emitting device 100.

The recess 160 is formed corresponding to the position of the threadingdislocation P1 or the convex pattern 111 of the substrate 110 to improvelow current and ESD characteristics of the semiconductor light emittingdevice 100 and increase light extraction efficiency, so that thereliability of the semiconductor light emitting device 100 can beimproved.

FIGS. 2 to 12 are views showing a method for manufacturing thesemiconductor light emitting device according to the first embodiment.

Referring to FIG. 2, the plurality of compound semiconductor layers 120,130, 140, and 150 are formed on the substrate 110.

The substrate 110 may comprise one selected from the group consisting ofaluminum oxide (Al₂0₃), gallium nitride (GaN), silicon carbide (SiC),zinc oxide (ZnO), silicon (Si), gallium phosphide (GaP), and galliumarsenide (GaAs).

As shown in FIGS. 2 and 3, a plurality of convex patterns 111 are formedon the substrate 110 with a uniform interval, and protrude in a convexlens shape or a hemispherical shape. The convex patterns 111 may beintegrally formed with the substrate 110, or may be independently formedon the substrate 110 by using a different material.

FIG. 4 is a view showing a convex pattern 112 of the substrate 111having a shape different from that of the convex patterns 111 shown inFIG. 3.

Referring to FIG. 4, the convex pattern 112 of the substrate 110 mayhave a rectangular shape. The convex pattern 112 may have a polyhedralshape having a predetermined size arranged in the form of a matrix or astripe, but the embodiment is not limited thereto.

A nitride semiconductor is grown from the substrate 110, and growingequipment comprises an electron beam, an evaporator, and a dual-typethermal evaporator. The nitride semiconductor may be grown through aphysical vapor deposition (PVD), a chemical vapor deposition (CVD), aplasma laser deposition (PLD), a sputtering scheme, or a metal organicchemical vapor deposition (MOCVD).

The undoped semiconductor layer 120 is formed on the substrate 110. Theundoped semiconductor layer 120 may comprise an AlGaN-basedsemiconductor that is not doped with a conductive dopant. Anothersemiconductor layer, for example, a buffer layer (not shown) may beformed between the substrate 110 and the undoped semiconductor layer120. The buffer layer may be one selected from the group consisting ofgallium nitride (GaN), aluminum nitride (AlN), aluminum gallium nitride(AlGaN), indium gallium nitride (InGaN), indium nitride (InN), indiumaluminum gallium nitride (InAlGaN), and aluminum indium nitride (AlInN).However, the embodiment is not limited to the semiconductor layerexisting between the substrate 110 and the first conductivesemiconductor layer 130.

The first conductive semiconductor layer 130, the active layer 140, andthe second conductive semiconductor layer 150 may be sequentially formedon the undoped semiconductor layer 120. Another layer may be formedamong the layers, but the embodiment is not limited thereto.

The first conductive semiconductor layer 130 comprises group III-Vcompound semiconductors doped with the first conductive dopant. Forexample, the first conductive semiconductor layer 130 may comprise oneselected from the group consisting of gallium nitride (GaN), aluminumnitride (AlN), aluminum gallium nitride (AlGaN), indium gallium nitride(InGaN), indium nitride (InN), indium aluminum gallium nitride(InAlGaN), and aluminum indium nitride (AlInN) that are semiconductormaterials having a composition formula of In_(x)Al_(y)Ga_(1−x−y)N(0≦x≦1, 0≦y≦1, 0≦x+y≦1). When the first conductive semiconductor layer130 is an N-type semiconductor layer, the first conductive dopantcomprises an N-type dopant such as silicon (Si), germanium (Ge), tin(Sn), selenium (Se), or tellurium (Te).

The active layer 140 may comprise a semiconductor material having acomposition formula of In_(x)Al_(y)Ga_(1−x−y)N (0≦x≦1, 0≦y≦1, 0≦x+y≦1),and may have a single quantum well structure or a multi-quantum wellstructure. The active layer 140 may comprise a material emitting colorlight such as blue light, red light, or green light, but the embodimentis not limited thereto. A conductive clad layer may be formed on and/orunder the active layer 140, and the conductive clad layer may comprisean AlGaN-based semiconductor.

The second conductive semiconductor layer 150 may comprise group III-Vcompound semiconductors doped with the second conductive dopant. Forexample, the second conductive semiconductor layer may comprise oneselected from the group consisting of gallium nitride (GaN), aluminumnitride (AlN), aluminum gallium nitride (AlGaN), indium gallium nitride(InGaN), indium nitride (InN), indium aluminum gallium nitride(InAlGaN), or aluminum indium nitride (AlInN) that are semiconductormaterials having a composition formula of In_(x)Al_(y)Ga_(1−x−y)N(0≦x≦1, 0≦y≦1, 0≦x+y≦1). When the second conductive semiconductor layer150 is a P-type semiconductor layer, the second conductive dopantcomprises a P-type dopant such as Mg or Ze.

Referring to FIG. 5, the third conductive semiconductor layer 170 may beformed on the second conductive semiconductor layer 150, and theelectrode layer 180 may be formed on the third conductive semiconductorlayer 170.

The third conductive semiconductor layer 170 comprises group III-Vcompound semiconductors doped with the first conductive dopant. Forexample, the third conductive semiconductor layer 130 may comprise oneselected from the group consisting of gallium nitride (GaN), aluminumnitride (AlN), aluminum gallium nitride (AlGaN), indium gallium nitride(InGaN), indium nitride (InN), indium aluminum gallium nitride(InAlGaN), and aluminum indium nitride (AlInN) that are semiconductormaterials having a composition formula of In_(x)Al_(y)Ga_(1−x−y)N(0≦x≦1, 0≦y≦1, 0≦x+y≦1). When the third conductive semiconductor layer170 is an N-type semiconductor layer, the first conductive dopantcomprises an N-type dopant such as silicon (Si), germanium (Ge), tin(Sn), selenium (Se), or tellurium (Te). The third conductivesemiconductor layer 170 may serve as an electrode contact layer, but theembodiment is not limited thereto.

The first conductive semiconductor layer 130, the active layer 140, thesecond conductive semiconductor layer 150, and the third conductivesemiconductor layer 170 may be defined as a light emitting structure.The first conductive semiconductor layer 130, the second conductivesemiconductor layer 150, and the third conductive semiconductor layer170 may be formed as a P-type semiconductor, an N-type semiconductor,and a P-type semiconductor, respectively. The light emitting structuremay comprise at least one of an N—P—N junction structure, a P—N—Pjunction structure, an N—P junction structure, and a P—N junctionstructure.

The electrode layer 180 is formed on the light emitting structure. Theelectrode layer 180 may be formed on the third conductive semiconductorlayer 170 using a transmissive electrode material. The electrode layer180 comprises at least one of indium tin oxide (ITO), indium zinc oxide(IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO),indium gallium zinc oxide (IGZO), indium gallium tin oxide (IGTO),aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide(GZO), IrOx, RuOx, RuOx/ITO, Ni/IrOx/Au and Ni/IrOx/Au/ITO, but theembodiment is not limited thereto. The electrode layer 180 may berealized by using a reflective electrode material (e.g., aluminum (Al)).

Referring to FIGS. 2 and 5, the threading dislocations P1 and P2 areformed at the positions of the convex patterns 111 of the substrate 110.The threading dislocations P1 and P2 are a crystal defect occurring inthe undoped semiconductor layer 120 due to the convex patterns 111 ofthe substrate 110, and extend to the surface of the electrode layer 180through the compound semiconductors 120 to 170. The threadingdislocations P1 and P2 vertically pass through the active layer 140perpendicularly to the active layer 140 to serve as a current path of aleakage current. For example, when a high voltage such as an ESD isinstantaneously applied, the high voltage flows along the threadingdislocations P1 and P2. In this case, the active layer 140 may bebroken, and optical power may be degraded.

Referring to FIGS. 5 and 6, a mask pattern 185 is formed on theelectrode layer 180. In order to form the mask pattern 185, a mask layeris prepared and a plurality of openings 186 are formed in the mask layerthrough a photo-mask process. The mask layer may comprise SiO₂, SiO_(x),SiN_(x), SiO_(x)N_(y) or the like.

The openings 186 are formed corresponding to the convex patterns 111 ofthe substrate 110, but not formed in a region A2 for the secondelectrode 193. The openings 186 of the mask pattern 185 may not beformed through an additional process, but simultaneously formed when therecesses 160 are formed.

The recesses 160 having the depth D1 are formed using the openings 186of the mask pattern 185. The recesses 160 may be formed through anetching process, for example, a dry etching (e.g., ICP) process and/or awet etching process. The dry etching process may employ equipment forinductively coupled plasma (ICP), reactive ion etching (RIE),capacitively coupled plasma (CCP), or electron cyclotron resonance(ECR).

The recesses 160 formed in the electrode layer 180 are formedcorresponding to the position of the convex patterns 111 of thesubstrate 110, thereby removing the threading dislocation P1 from theelectrode layer 180.

The recesses 160 may be formed to the upper portion of the secondconductive semiconductor layer 150 from the electrode layer 180corresponding to the convex patterns 111 of the substrate 110.Accordingly, treading dislocations may be removed from the upper portionof the second conductive semiconductor layer 150, the third conductivesemiconductor layer 170, and the electrode layer 180.

The recesses 160 may not be formed in a predetermined region of theelectrode layer 180, for example, the region A2 for the secondelectrode. This is because the second electrode can be blocked to makecontact with the threading dislocation P2 by the recesses 160, therebypreventing an ESD characteristic or a low current characteristic frombeing degraded.

FIG. 7 is a side sectional view showing a recess shape according to thefirst embodiment.

Referring to FIGS. 7A to 7D, the reverse conical shape recess 160, apolyhedral recess 161, a trapezoidal shape recess 162, and a reversetrapezoid shape recess 163 may be formed. In addition, the recess shapecomprises a polygonal column shape, a cylindrical shape, or ahemispherical shape, and may be changed in the technical scope of theembodiment.

As shown in FIG. 7A, the recess 160 has the maximum width D2 of about 10nm to about 3000 nm, and the depth of about 10 nm to about 1000 nm. Themaximum width D2 of the recess 160 may be changed according to the sizeof the convex pattern of the substrate, and the depth D1 may be changedaccording to the thickness of the compound semiconductor layers.

FIG. 8 is a view showing an opening shape of the mask pattern 185according to the first embodiment.

Referring to FIG. 8, the openings 186 of the mask pattern 185 may have apolygonal shape (e.g., hexagonal shape). Accordingly, the surficialshape of the recesses may have a hexagonal shape. In this case, theopenings 186 of the mask pattern 185 may have a polygonal shape beyond atriangular shape.

The openings 186 may have polygons arranged with a uniform interval oran irregular interval, and the width D2 of the openings 185 may bechanged according to a chip size.

The openings 186 of the mask pattern 185 may not be formed in the regionA2 for the second electrode.

FIG. 9 is a view showing a modified opening shape of the mask pattern185 according to the first embodiment.

Referring to FIG. 9, an opening 186A of the mask pattern 185 may have acircular shape. Accordingly, the surficial shape of the recesses mayhave a circular shape.

Referring to FIGS. 6 and 10, the mask pattern 185 is removed. The maskpattern 185 may be removed through a dry etching process, but theembodiment is not limited thereto.

Referring to FIGS. 10 and 11, a predetermined region of the firstconductive semiconductor layer 130 is exposed through a mesa etchingprocess. In this case, the mesa etching process is performed from aportion of the electrode layer 180 to an upper portion of the firstconductive semiconductor layer 130, thereby exposing the upper portionof the first conductive semiconductor layer 130. Such mesa etchingprocess is to make boundaries between chips and expose a region for thefirst electrode.

Referring to FIGS. 11 and 12, the first electrode 191 is formed on thefirst conductive semiconductor layer 130, and the second electrode 193is formed in the region for the second electrode 193 on the electrodelayer 180. The second electrode 193 may be formed on the electrode layer180, or may be formed to make contact with the electrode layer 180 andthe third conductive semiconductor layer 170.

The sequence of the etching process of forming the recess 160 and themesa etching process may be changed, and the two etching processes maybe simultaneously performed. However, the embodiment is not limitedthereto.

The electrode layer 180 is provided on the upper surface of the thirdconductive semiconductor layer 170 to diffuse a current applied to thesecond electrode 193. The current is applied to the third conductivesemiconductor layer 170, the second conductive semiconductor layer 150,and the active layer 140.

The recesses 160 is formed corresponding to the position of thethreading dislocation P1 or the convex patterns 111 of the substrate110, thereby blocking the current applied to the threading dislocationP1 through the electrode layer 180. Accordingly, the low currentcharacteristic and the ESD characteristic of the light emitting device100 can be improved, and the light extraction efficiency can be improvedby the recess 160.

FIG. 13 is a sectional view showing a semiconductor light emittingdevice according to a second embodiment. The same reference numeralswill be assigned to elements identical to those of the first embodiment,and details thereof will be omitted.

Referring to FIG. 13, a semiconductor light emitting device 100Acomprises the substrate 110 having the convex patterns 111, the undopedsemiconductor layer 120, the first conductive semiconductor layer 130,the active layer 140, the second conductive semiconductor layer 150, theelectrode layer 180, the recesses 160, the first electrode 191, and thesecond electrode 193.

The electrode layer 180 may be formed on the second conductivesemiconductor layer 150, and the recesses 160 may be formed from theelectrode layer 180 to the upper portion of the second conductivesemiconductor layer 150.

The semiconductor device 100A has a structure in which the secondconductive semiconductor layer 150 and the electrode layer 180 areprovided on the active layer 140, and the third conductive semiconductorlayer 170 is removed. In this case, if the first conductivesemiconductor layer 130 is an N-type semiconductor, the secondconductive semiconductor 150 layer may be a P-type semiconductor. If thefirst conductive semiconductor layer 130 is a P-type semiconductor, thesecond conductive layer 150 may be an N-type semiconductor.

FIG. 14 is a side sectional view showing a semiconductor light emittingdevice 100B according to a third embodiment. The same reference numeralswill be assigned to elements identical to those of the first embodiment,and details thereof will be described in order to avoid redundancy.

Referring to FIG. 14, the semiconductor light emitting device 100Bcomprises a plurality of recesses 160A having a depth D3 deeper thanthat of the previous embodiment.

The recesses 160A correspond to the position of the threadingdislocation P1, and may be formed to the upper portion of the firstconductive semiconductor layer 130. In other words, the recesses 160Aextend from the electrode layer 180 to the upper portion of the firstconductive semiconductor layer 130 through the third conductivesemiconductor layer 170, the second conductive semiconductor layer 150,and the active layer 140. The recesses 160A may have a reverse conicalshape or a polyhedral shape.

The semiconductor light emitting device 100B allows a current applied tothe first conductive semiconductor layer 130 and the electrode layer 180to be distributed without being concentrated on the threadingdislocation P1 due to the recesses 160A, so that a low currentcharacteristic or an ESD characteristic can be improved.

The recesses 160A and a transmissive insulating layer 167 may be formedto a predetermined depth from the electrode layer 181, the thirdconductive semiconductor layer 170 or the second conductivesemiconductor layer 150, and this may be changed within the technicalscope of the embodiment.

FIG. 15 is a side sectional view showing a semiconductor light emittingdevice 100C according to a fourth embodiment. The same referencenumerals will be assigned to elements identical to those of the firstembodiment, and details thereof will be described in order to avoidredundancy.

Referring to FIG. 15, the semiconductor light emitting device 100Ccomprises the recesses 160 having the transmissive insulation layer 167.The insulation layer 167 is filled in the recesses 160, and comprisessilicon oxide (SiO₂), silicon nitride (Si₃N₄), aluminum oxide (Al₂O₃),or titanium oxide (TiO₂). However, the embodiment is not limitedthereto.

Since the insulating layer 167 has an insulation characteristic, acurrent applied to the electrode layer 180 can be distributed. Inaddition, the insulating layer 167 may be formed in the recess 160Ashown in FIG. 14, but this may be changed within the technical scope ofthe embodiment.

FIG. 16 is a side sectional view showing a semiconductor light emittingdevice 100D according to a fifth embodiment. The same reference numeralswill be assigned to elements identical to those of the first embodiment,and details thereof will be described in order to avoid redundancy.

Referring to FIG. 16, the semiconductor light emitting device 100D maybe realized as a vertical semiconductor light emitting device. Thesemiconductor light emitting device 100D comprises the substrate 110(see FIG. 1) on which the undoped semiconductor layer 120, the firstconductive semiconductor layer 130, the active layer 140, the secondconductive semiconductor layer 150, and the third conductivesemiconductor layer 170 are sequentially formed.

An electrode layer 183 is formed on the third conductive semiconductorlayer 170, and the recesses 160 are formed to a predetermined depth D4from the electrode layer 183 corresponding to the threading dislocationP1. The electrode layer 182 may comprise a reflective electrode materialsuch as aluminum (Al), silver (Ag), palladium (Pd), rhodium (Rh),platinum (Pt), or iridium (Ir).

The insulating layer 167 is filled in the plural recesses 160, andcomprises one selected from the group consisting of silicon dioxide(SiO₂), silicon nitride (Si₃N₄), aluminum oxide (Al₂O₃), or titaniumoxide (TiO₂). However, the embodiment is not limited thereto.

A conductive support member 185 is formed on both the electrode layer183 and the insulating layer 167. The conductive support member 185 maycomprise copper (Cu), gold (Au), or a carrier wafer (e.g., Si, Ge, GaAs,ZnO, or SiC). The conductive support member 185 may be formed through anelectrolytic plating scheme or may be attached to the electrode layer183 and the insulating layer 176 through a bonding scheme.

Thereafter, the substrate 110 (see FIG. 1) and the undoped semiconductorlayer 120 may be removed through a physical scheme and/or a chemicalscheme. The substrate 110 (see FIG. 1) may be physically removed througha laser lift off (LLO) scheme. In addition, the substrate 110 may bechemically removed together with the undoped semiconductor layer 120(see FIG. 1) by using a wet etching solution, but the embodiment is notlimited thereto. The first electrode 191 is formed under the firstconductive semiconductor layer 130.

The recesses 160 and the transmissive insulating layer 167 may be formedto a predetermined depth from the electrode layer 183, the thirdconductive semiconductor layer 170, or the second conductivesemiconductor layer 150, and these features may be changed within thetechnical scope of the embodiment.

The semiconductor light emitting device 100D can distribute a current,which is applied by the conductive support member 185, by the recesses160, thereby preventing the current from being concentrated onto thethreading dislocation P1.

A roughness pattern may be formed under the first conductivesemiconductor layer 130, and the roughness pattern can improve lightextraction efficiency.

Different from the structure, the semiconductor light emitting device100D may comprise a transmissive electrode layer (not shown) formedunder the first conductive semiconductor 130, and lower recesses (notshown) formed to a predetermined depth from the electrode layer and thefirst conductive semiconductor layer 130 corresponding to the threadingdislocation P1. In addition, the transmissive insulating layer 167 maybe formed in the lower recess. The first electrode 191 may be formedunder the transmissive electrode layer (not shown).

Meanwhile, the technical characteristics of the first to fifthembodiments are applicable to other embodiments.

Although the embodiment has been made in relation to the compoundsemiconductor light emitting device comprising the N—P junctionstructure as an example, the compound semiconductor light emittingdevice comprising an N—P—N structure, a P—N structure or a P—N—Pstructure can be implemented.

In the description of the embodiment, it will be understood that, when alayer (or film), a region, a pattern, or a structure is referred to asbeing “on (above/over/upper)” or “under (below/down/lower)” anothersubstrate, another layer (or film), another region, another pad, oranother pattern, it can be directly on the other substrate, layer (orfilm), region, pad or pattern, or intervening layers may also bepresent. Furthermore, it will be understood that, when a layer (orfilm), a region, a pattern, a pad, or a structure is referred to asbeing “between” two layers (or films), regions, pads or patterns, it canbe the only layer between the two layers (or films), regions, pads, orpatterns or one or more intervening layers may also be present. Thus, itshould be determined by technical idea of the invention.

Any reference in this specification to “one embodiment,” “anembodiment,” “example embodiment,” etc., means that a particularfeature, structure, or characteristic described in connection with theembodiment is comprised in at least one embodiment of the invention. Theappearances of such phrases in various places in the specification arenot necessarily all referring to the same embodiment. Further, when aparticular feature, structure, or characteristic is described inconnection with any embodiment, it is submitted that it is within thepurview of one skilled in the art to effect such feature, structure, orcharacteristic in connection with other ones of the embodiments.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

1. A semiconductor light emitting device comprising: a first conductivesemiconductor layer; an active layer on the first conductivesemiconductor layer; and a second conductive semiconductor layercomprising a plurality of recesses on the active layer.
 2. Thesemiconductor light emitting device of claim 1, wherein the recess ofthe second conductive semiconductor layer is formed at a position ofthreading dislocation of the second conductive semiconductor layer. 3.The semiconductor light emitting device of claim 2, comprising a thirdconductive semiconductor layer and/or an electrode layer, whichcomprises a recess connected to the recess of the second conductivesemiconductor layer, on the second conductive semiconductor layer. 4.The semiconductor light emitting device of claim 1, wherein the recessof the second conductive semiconductor layer extends to an upper portionof the first conductive semiconductor layer.
 5. The semiconductor lightemitting device of claim 1, comprising a convex pattern, whichcorresponds to the recess of the second conductive semiconductor layer,under the first conductive semiconductor layer.
 6. The semiconductorlight emitting device of claim 2, comprising a substrate, whichcomprises a convex pattern corresponding to the recess of the secondconductive semiconductor layer, under the first conductive semiconductorlayer; and a buffer layer and/or an undoped semiconductor layerinterposed between the substrate and the first conductive semiconductorlayer.
 7. The semiconductor light emitting device of claim 1, whereinthe recess has at least one of a polyhedral shape, a reverse conicalshape, a polygonal column shape, a cylindrical shape, and ahemispherical shape.
 8. The semiconductor light emitting device of claim1, comprising a transmissive insulating layer in the recess of thesecond conductive semiconductor layer.
 9. The semiconductor lightemitting device of claim 1, comprising: a first electrode under thefirst conductive semiconductor layer; an electrode layer comprising aninsulating layer in the recess on the second conductive semiconductorlayer; and a conductive support member on the electrode layer.
 10. Thesemiconductor light emitting device of claim 3, wherein the electrodelayer comprises one selected from the group consisting of indium tinoxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO),indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO),indium gallium tin oxide (IGTO), aluminum zinc oxide (AZO), antimony tinoxide (ATO), gallium zinc oxide (GZO), IrOx, RuOx, RuOx/ITO, Ni/IrOx/Au,and Ni/IrOx/Au/ITO.
 11. A semiconductor light emitting devicecomprising: a substrate comprising a plurality of convex patterns; alight emitting structure comprising a plurality of compoundsemiconductor layers on the substrate; an electrode layer on the lightemitting structure; and a recess formed from the electrode layer to apredetermined position of the light emitting structure corresponding tothe convex pattern of the substrate.
 12. The semiconductor lightemitting device of claim 11, wherein the convex pattern comprises atleast one of a lens shape, a hemispherical shape, a polyhedral shape,and a stripe shape.
 13. The semiconductor light emitting device of claim11, wherein the recess has a maximum width of about 10 nm to about 3000nm and a depth of about 10 nm to about 1000 nm.
 14. The semiconductorlight emitting device of claim 11, wherein the recess comprises atransmissive insulating layer.
 15. The semiconductor light emittingdevice of claim 11, wherein the light emitting structure comprises: afirst conductive semiconductor layer on the substrate; an active layeron the first conductive semiconductor layer; and a second conductivesemiconductor layer interposed between the active layer and theelectrode layer, in which the recess is formed from the electrode layerto the second conductive semiconductor layer.
 16. The semiconductorlight emitting device of claim 15, comprising a third conductivesemiconductor layer doped with a first conductive dopant between thesecond conductive semiconductor layer and the electrode layer.
 17. Asemiconductor light emitting device comprising: a light emittingstructure having a threading dislocation and comprising a firstconductive semiconductor layer, an active layer on the first conductivesemiconductor layer, and a second conductive semiconductor layer on theactive layer; an electrode layer on the light emitting structure; and aplurality of recesses formed from the electrode layer to a predetermineddepth of the light emitting structure corresponding to the treadingdislocation.
 18. The semiconductor light emitting device of claim 17,wherein the recesses are formed to an upper portion of the secondconductive semiconductor layer or the first conductive semiconductorlayer.
 19. The semiconductor light emitting device of claim 18, whereinthe recesses of the electrode layer are filled with a transmissiveinsulating layer, and the electrode layer comprises a transmissiveelectrode material or a reflective electrode material.
 20. Thesemiconductor light emitting device of claim 17, comprising a substratehaving a convex pattern, which corresponds to each recess or thethreading dislocation, under the first conductive semiconductor layer.